Geochemical production allocation is analogous to the following scenario. A glass of water (Water A) contains 100 ppm sodium dissolved in the water. A second glass of water (Water B) contains 200 ppm sodium. When unknown amounts of each are mixed, the mixture is found to contain 150 ppm sodium. Intuitively, we know that the mixture contains 50% Water A and 50% Water B because 150 ppm is the midpoint between 100 ppm and 200 ppm. In this example, the abundance of one chemical component in the water (sodium) made chemical allocation of the commingled water possible. Similarly, a difference in the abundance of any one chemical compound in the hydrocarbons from each of two reservoirs in an oil field is sufficient to serve as a natural tracer for chemically allocating commingled production.